JP2007121649A - Method for cleaning photoreceptor, image forming apparatus, program, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoreceptor cleaning method capable of performing cleaning for removing foreign substances stuck to the surfaces of photoreceptors without using an exclusive abrasive paper and to provide an image forming apparatus. <P>SOLUTION: Recording paper P is carried and brought into contact with photoreceptors of all photoreceptor drums 3a to 3d and the vicinity of a rear end of the recording paper P is held between a pair of resist rollers 14 and stopped. Then, the photoreceptor drums 3a to 3d are rotationally driven to clean the photoreceptors. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  In an image forming apparatus for forming an image on a recording medium by an electrophotographic method or an electrostatic recording method such as a copying machine, a printer, a facsimile, or a printing machine, the present invention cleans the surface of a carrier such as a photosensitive drum, The present invention relates to an image forming apparatus capable of removing foreign matter adhering to the surface of a photoreceptor.

  In general, an electrostatic latent image is formed on a surface layer of a photosensitive drum of an electrophotographic image forming apparatus, and the electrostatic latent image is developed with a developer such as toner to form an unfixed developer image. The Then, the sheet-form recording medium is brought into contact with the photosensitive drum by the transfer unit, and the developer image is transferred to the recording medium. After the transfer, the developer image is applied to the recording medium by heating and pressurizing by the fixing unit. Let it settle.

  For example, in the photosensitive drum, fine particles of the photoconductive material are dispersed in a mixed liquid obtained by melting a charge transporting substance and a resin, and this is applied to the surface of the drum base and dried to form the photosensitive layer. A photoreceptor drum provided with a so-called organic photoreceptor that is formed is widely used.

  The surface layer of the photosensitive drum may be affected by filming or toner black spots if foreign matter such as powder developer residue or paper pieces adheres or deteriorates. Need to be removed. For this reason, a cleaning blade for scraping off the attached foreign matter is provided in contact with the photosensitive drum.

  However, if the contact pressure of this blade is too low, the foreign matter adhering to the surface of the photosensitive drum cannot be sufficiently removed and the dirt becomes noticeable, causing adverse effects such as filming, and the performance is reduced. Performance recovery is achieved by bringing the surface layer of the photosensitive drum into contact with the surface to some extent.

  On the other hand, if the contact pressure of the blade is too large, there is a possibility that a problem of uneven wear occurs on the surface of the photosensitive drum due to the polishing action of the blade end.

  Therefore, a technique for appropriately cleaning the surface layer of the photosensitive drum is necessary. Note that “polishing” described in the specification of the present application means that the photosensitive layer is scraped at least.

  Japanese Patent Application Laid-Open No. H10-228707 discloses a conventional technique for polishing the surface layer of a photosensitive drum to recover its performance.

  In this prior art, the driving force of the driving motor is transmitted to the conveying roller and the photosensitive drum via the first and second clutches, respectively. That is, normally, in the conveyance of the recording paper, the first clutch is turned on to transmit the driving force of the drive motor to the conveyance roller, and the recording paper is conveyed from the paper feeding unit to the transfer unit by the conveyance roller. The second clutch is also turned on, and development and transfer are performed at an appropriate timing by the photosensitive drum.

On the other hand, at the time of polishing, a polishing sheet provided with abrasive particles for polishing the photosensitive drum of the copying machine is conveyed into the copying machine main body instead of the recording paper. Then, in a state where the polishing sheet exists on the photosensitive drum, the first clutch is turned off to stop the conveyance of the polishing sheet. With the polishing sheet in contact with the photosensitive drum, the second clutch is turned on to transmit the driving force of the drive motor to the photosensitive drum, and the photosensitive drum is rotated to polish the surface layer with the polishing sheet.
Japanese Patent Laid-Open No. 5-204282 (released on August 13, 1993)

  However, in the technique of Patent Document 1 described above, a dedicated polishing sheet must be set in the supply unit separately from the recording paper, only for the purpose of removing the foreign matter adhering to the surface of the photoreceptor. In addition, providing a dedicated abrasive sheet supply unit separately from the paper supply unit complicates the device configuration around the paper supply unit such as the conveyance unit of the copying machine. It becomes an obstacle to improvement of economy and maintenance.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to clean a photoconductor capable of performing cleaning to remove foreign matter adhering to the surface of the photoconductor without using a dedicated polishing sheet. A method, an image forming apparatus, a program for executing a photosensitive member cleaning method, and a recording medium on which the program is recorded.

  In order to solve the above problems, the method for cleaning the photoconductor of the present invention forms a contact stop state in which the recording paper conveyed through the recording paper conveyance path is brought into contact with the surface of the photoconductor of the photosensitive drum and stopped. The surface of the photoconductor is cleaned by performing a contact stop state forming step and a rotation driving step of rotating the photoconductor drum in the contact stop state.

  According to the above invention, the recording paper is transported along the transport path and is brought into contact with the surface of the photoconductor of the photoconductor drum and stopped. Next, the photosensitive drum is rotationally driven in this contact stopped state. At this time, the recording paper is brought into sliding contact with the surface of the photoconductor, whereby the surface of the photoconductor is cleaned, and foreign matter adhered such as filming can be removed. Since a recording sheet may be used for cleaning, a dedicated polishing sheet is unnecessary.

  As described above, there is an effect that it is possible to realize a photoconductor cleaning method capable of performing cleaning to remove foreign matters attached to the photoconductor surface without using a dedicated polishing sheet.

  In addition, since the recording paper is used for cleaning, the same paper feeding mechanism and transport path as the recording paper can be used as they are, and the image forming apparatus to which this cleaning method is applied can be reduced in size, improved in economy, and improved in maintenance. There is an effect that it is not inhibited.

  In order to solve the above-described problems, the photosensitive member cleaning method of the present invention is characterized in that, in the rotational driving step, the number of rotations in the rotational driving of the photosensitive drum is 1 to 5 times.

  According to the above invention, the entire surface of the photosensitive member can be cleaned by rotating the photosensitive drum once or more, and the recording paper can be cleaned by rotating the photosensitive drum less than five times. The effect of reducing the cleaning effect due to the dirt adhering to the surface and preventing the surface of the photoreceptor from being scratched can be achieved.

In order to solve the above-described problem, the photoconductor cleaning method of the present invention performs an additional transport movement step of transporting the recording paper used for cleaning further downstream in the transport direction after the rotation driving step.
After the additional transport movement step, the contact stop state forming step and the rotation driving step are repeated using the recording paper transported and moved by the additional transport movement step with respect to the same photosensitive drum. Yes.

  According to the above invention, since the surface of the photoconductor is cleaned a plurality of times at different locations on the same recording paper, the cleaning effect is increased.

  In order to solve the above-described problem, the method for cleaning a photoconductor of the present invention is configured such that when there are a plurality of the photoconductor drums along the transport path, one recording sheet is used in the contact stop state forming step. All the photosensitive drums are brought into contact with each other, and in the rotational driving step, all the photosensitive drums are rotationally driven.

  According to the above-described invention, the effect of being able to clean the surfaces of all the photoconductors at once is provided for an image forming apparatus including a plurality of photoconductor drums.

  In order to solve the above problems, the method for cleaning a photoconductor of the present invention further conveys the recording paper used for cleaning after the rotation driving step by a distance shorter than the distance between adjacent photoconductor drums. An additional transport movement step for transporting the recording material downstream in the direction, and after the additional transport movement step, using the recording paper transported by the additional transport movement step to all the photosensitive drums, the contact The stop state forming step and the rotation driving step are repeated.

  According to the above invention, there is an effect that the surfaces of all the photoconductors can be cleaned a plurality of times at different fresh locations on the same recording paper.

  In order to solve the above problems, the method for cleaning a photoconductor of the present invention uses a single sheet of the recording paper when there are a plurality of the photoconductor drums along the transport route, and the most upstream of the transport route. The contact stop state forming step and the rotation driving step while conveying the recording paper between the adjacent photosensitive drums one by one from the photosensitive drum on the side toward the photosensitive drum on the downstream side. It is characterized by performing.

  According to the above-described invention, there is an effect that it is possible to perform cleaning on all of the plurality of photoconductors even when using a recording paper having a small size that does not contact all the photoconductor drums at once.

  In order to solve the above-described problems, the method for cleaning a photoconductor of the present invention provides the contact when cleaning the surface of the photoconductor of the photoconductor drum positioned second or later in the transport direction of the transport path. In the stop state forming step, the recording sheet is sandwiched between the upstream photosensitive drum and the transfer roller provided to perform image transfer from the upstream photosensitive drum. And stop.

  According to the above-described invention, when a small-size recording sheet is used, the surfaces of the plurality of photoconductors can be easily and sequentially cleaned without providing a special mechanism for stopping the recording sheet at a plurality of predetermined positions. There is an effect that can be.

  In order to solve the above problems, the image forming apparatus of the present invention is an image forming apparatus that forms an image on a recording sheet using a photosensitive drum, and the recording sheet is conveyed to the surface of the photosensitive element of the photosensitive drum. A contact stop state in which the recording paper conveyed through the path is brought into contact and stopped is formed, and the surface of the photoreceptor is cleaned by rotationally driving the photoreceptor drum in the contact stop state.

  According to the above-described invention, there is an effect that it is possible to realize an image forming apparatus capable of performing cleaning for removing foreign matters attached to the surface of the photoreceptor without using a dedicated polishing sheet.

  In addition, since the recording paper is used for cleaning, the same paper feeding mechanism and conveyance path as the recording paper can be used as they are, and the downsizing, improvement in economic efficiency, and improvement in maintenance performance of the image forming apparatus are not hindered. There is an effect.

  In order to solve the above-described problems, a program according to the present invention causes a computer to execute the method for cleaning the photosensitive member.

  According to the above invention, if the computer configuration is provided, the method for cleaning the photoconductor can be executed, so that the method can be provided with versatility.

  In order to solve the above-described problems, the recording medium of the present invention records the above-described program in a computer-readable manner.

  According to the above invention, it is possible to easily distribute the program for executing the method for cleaning the photosensitive member, and it is possible to easily incorporate the program into the computer.

  As described above, the method for cleaning the photoconductor of the present invention cleans the surface of the photoconductor by performing the contact stop state forming step and the rotation driving step.

  In addition, as described above, the image forming apparatus of the present invention forms a contact stop state in which the recording sheet conveyed through the recording sheet conveyance path is brought into contact with the surface of the photosensitive element of the photosensitive drum and stopped. The surface of the photoconductor is cleaned by rotationally driving the photoconductor drum in the contact stopped state.

  As described above, there is an effect that it is possible to realize a photoconductor cleaning method and an image forming apparatus that can perform cleaning to remove foreign matter adhering to the surface of the photoconductor without using a dedicated polishing sheet.

  An embodiment of the present invention will be described below with reference to FIGS.

  FIG. 6 shows a configuration of an electrophotographic image forming apparatus 100 according to the present embodiment. Here, the image forming apparatus 100 is described as a printer unit of a copying machine, but it may be a multi-function machine to which a scanner function, a facsimile function, or the like is added, or a facsimile machine.

  The image forming apparatus 100 is a tandem type image forming apparatus, and includes four image forming stations for Bk (black), C (cyan), M (magenta), and Y (yellow). The image forming station for Bk is on the uppermost stream side of the recording paper conveyance path, and includes a charger 1a, a developing device 2a, a transfer roller 6a, a cleaning device 4a, and a charge eliminating device 5a around the photosensitive drum 3a. ing. The image forming station for C is one downstream side of the image forming station for Bk. Around the photosensitive drum 3b, a charger 1b, a developing device 2b, a transfer roller 6b, a cleaning device 4b, and a charge eliminating device 5b. It has. The image forming station for M is on the downstream side of one image forming station for C, and a charger 1c, a developing device 2c, a transfer roller 6c, a cleaning device 4c, and a charge eliminating device 5c are provided around the photosensitive drum 3c. I have. The Y image forming station is one downstream side of the M image forming station. Around the photosensitive drum 3d, the charger 1d, the developing device 2d, the transfer roller 6d, the cleaning device 4d, and the charge eliminating device 5d are provided. It has. These image forming stations execute a so-called Carlson process. Although not shown, a laser scanning unit is provided above the photosensitive drums 3a to 3d for exposing the photosensitive members charged by the chargers 1a to 1d.

  In order to form a conveyance path for each image forming station, a transfer belt 7 is provided that is stretched between a driving roller 71 and a pulley 73 that also serves as a tension roller. The image is rotated in the B direction from the Bk image forming station to the C → M → Y image forming station. The transfer belt 7 is provided so as to pass between the photosensitive drum and the transfer roller of each image forming station. The transfer recording sheet 7 is held on the surface of the transfer belt 7 on the photosensitive drum 3a side, and Bk. From the image forming station to the Y image forming station. Further, the rotation path of the transfer belt 7 opposite to the image forming station is given tension by tension rollers 72 and 74 from the inside. Further, a cleaning device 9 for cleaning the surface of the transfer belt 7 is provided outside the rotation path. The unit of the transfer belt 7 and the transfer rollers 6a to 6d can be rotated downward with the pulley 73 side as a fulcrum, so that only the Bk image forming station can perform the image forming operation. It is also like.

  A paper feed cassette 10 is provided below the image forming station and the transfer belt 7 and holds recording paper. A pickup roller 16 that feeds recording paper is provided at the paper feed port of the paper feed cassette 10, and a transport path S <b> 1 is provided from this paper feed port to the front of the pulley 73 of the transfer belt 7. A registration roller pair 14 is provided at the end of the conveyance path S1, that is, in front of the pulley 73, thereby adjusting the timing of sending the conveyed recording sheet toward the image forming station. A recording paper photodetection unit is provided that includes a pair of an illumination 21 and a line sensor 22 disposed adjacent to the downstream side of the conveyance path of the registration roller pair 14 so as to sandwich the conveyance path from above and below. Is passed between the illumination 21 and the line sensor 22, it is detected that the recording sheet is supplied to the Bk image forming station. A manual feed tray may be provided on the outer surface of the casing 35 of the image forming apparatus 100. A recording sheet used for cleaning the photosensitive member, which will be described later in this embodiment, may be supplied from the manual feed tray or may be supplied from the paper feed cassette 10.

  A fixing device 12 is provided further downstream of the transfer path of the transfer belt 7 and fixes an image formed on the recording paper through each image forming station. The fixing device 12 is composed of a pair of a heating roller 31 and a pressure roller 32, and presses and heats an image by passing a recording sheet between both rollers.

  On the downstream side of the fixing device 12, a discharge tray 33 and a conveyance path S2 are provided. The discharge tray 33 is provided so as to protrude from the outer surface of the casing 35 of the image forming apparatus 100, and the conveyance path S <b> 2 extends upward inside the casing 35 of the image forming apparatus 100 and is then bent in the horizontal direction. , And is provided to face the paper discharge tray 15 formed on the upper surface of the housing 35. A switching point 34 for determining whether to connect the path to the discharge tray 33 or the path to the transport path S2 is provided from the exit of the fixing device 12. A paper discharge roller 25 is provided at the end of the transport path S2.

  A control unit 50 that controls various operations such as image formation and conveyance of recording paper is provided above the image forming station. FIG. 7 shows a specific configuration of the control unit 50 and a control block configuration of the image forming apparatus 100 centering on the control unit 50.

  The control unit 50 is composed of a CPU and a program combined therewith, and includes a high pressure control means 50a, a feed speed control means 50b, a transport speed control means 50c, a transfer speed control means 50d, a cleaning speed control means 50e, and the like. I have. The control unit 50 controls an operation unit 51 that executes an image forming operation and a recording sheet conveying operation of the image forming apparatus 100 via an interface. The operation unit 51 includes a process driving unit 51a, a high voltage control unit 51b, a transfer control unit 51c, and the like.

  The high voltage control means 50 a of the control unit 50 sends a high voltage application control signal to the high voltage control unit 51 b of the operation unit 51. Under this control, the high voltage controller 51b applies the grid voltage of the chargers 1a to 1d, the developing bias of the developing devices 2a to 2d, the transfer voltage of the transfer rollers 6a to 6d, and the like.

  The feed speed control means 50 b of the control unit 50 sends a control signal to the process drive unit 51 a of the operation unit 51. In response to this control, the process driving unit 51a performs control for adjusting the timing of the entire process such as the driving timing of the photosensitive drums 3a to 3d and the transfer rollers 6a to 6d.

  The conveyance speed control means 50 c of the control unit 50 sends a control signal to the conveyance control unit 51 c of the operation unit 51. In response to this control, the conveyance control unit 51c drives the drive motors of the respective conveyance rollers, controls the speed of the photosensitive drums 3a to 3d, controls the sheet feed clutch that contacts and separates the driving force transmission shafts of the respective conveyance rollers, and In addition, the transfer clutches for controlling the drive force transmission shafts of the transfer rollers 6a to 6d and moving the transfer roller up and down are controlled.

  Further, the transfer speed control means 50 d of the control unit 50 sends a control signal to the transport control unit 51 c of the operation unit 51. In response to this control, the conveyance control unit 51c controls the speed of the driving roller 71 of the transfer belt 7 and the speed of the transfer rollers 6a to 6d in accordance with the speed of the photosensitive drums 3a to 3d.

  The cleaning speed control means 50e of the control unit 50 sends a signal for controlling the speed of the photosensitive drums 3a to 3d, the transfer rollers 6a to 6d, the driving roller 71, and the like to the process driving unit of the operating unit 51 when cleaning the photosensitive member to be described later. 51a and the conveyance control unit 51c.

  In addition, the image forming apparatus 100 is provided with a key operator unit 52. From this, an operation condition setting instruction and an operation start instruction can be sent to the control unit 50 via an interface.

  Next, a method for cleaning the photoreceptors of the photoreceptor drums 3a to 3d in the image forming apparatus 100 having the above configuration will be described below. Here, the photoreceptor is an organic photoreceptor as described above.

FIG. 1 shows a state of the image forming apparatus 100 when the photosensitive member is cleaned. The configuration of the image forming apparatus 100 is shown in a simplified manner. As shown in the figure, in the present embodiment, a thick recording paper P having a thickness greater than 70 g / m ² is used as a cleaning sheet. Use one sheet. The cardboard should have a basis weight of 100 g / m ² or more, and the surface should be as rough as possible, for example, 60 Beck seconds (smoothness according to Beck smoothness test method, JISP 8119) or less. In FIG. 1, the size of the recording paper P is A3.

  This recording sheet is conveyed from the manual feed tray and the paper feed cassette 10 to the image forming station through the same conveyance path as that of general recording sheets. The orientation of the recording paper P is such that the long side is along the transport direction. The conveyed recording paper P is sandwiched between the registration roller pair 14 in the vicinity of the rear end, and stops in a state where it is in contact with the surfaces of all the photoreceptors of the photoreceptor drums 3a to 3d. Thus, first, the contact stop state forming step for forming the contact stop state of the recording paper P is performed. Next, a rotation driving step for simultaneously rotating the photosensitive drums 3a to 3d in the contact stop state is performed. At this time, the recording paper P is brought into sliding contact with the surface of the photoconductor, so that the surface of the photoconductor is cleaned and foreign matter such as filming can be removed. Since the recording paper P may be used for cleaning, a dedicated polishing sheet is not necessary.

  Thereby, the cleaning which removes the foreign material adhering to the photoreceptor surface can be performed without using a dedicated polishing sheet. Further, since the recording paper P is used for cleaning, the same paper feed mechanism and transport path as the recording paper can be used as they are, and the downsizing, improvement in economic efficiency, and improvement in maintenance performance of the image forming apparatus 100 are hindered. There is no.

  Next, an appropriate number of rotations of the photosensitive drums 3a to 3d in the rotation driving step in the cleaning will be described.

  Table 1 shows the result of examining the contrast between the rotational speed of the photosensitive drum and the cleaning effect.

  In the case of 0.5 times, a range that cannot be cleaned occurs on the surface of the photoreceptor. The cleaning effect was obtained to the extent that there was no practical problem at one time, and a large cleaning effect was obtained at three times and five times. In addition, it was found that the cleaning effect deteriorates as a result of the toner adhering to the photoconductor moving and accumulating on the recording paper P in 7 times. In 10 times, the photoconductor was further scratched.

  As a result of thoroughly examining such a comparison, the number of rotations is one or more times that the entire surface of the photosensitive member can be cleaned, and the cleaning effect is reduced due to the dirt adhering to the recording paper P. It has been found that it is desirable that the number of times is not more than 5 times so that the surface of the film can be prevented from being scratched.

  Moreover, the above cleaning can be performed a plurality of times. To do this, after the rotational drive step, an additional transport movement step is performed in which the recording paper P used for cleaning is transported further downstream in the transport direction. Since there are a plurality of photosensitive drums, the transport movement distance at this time is such that the portion once used for cleaning the recording paper P does not come into contact with the photosensitive drums of other colors on the downstream side. The distance is shorter than the distance. In this way, the surfaces of all the photoreceptors can be cleaned a plurality of times at different fresh locations on the same recording paper P. The distance between the photosensitive drums is a process pitch, for example, about 95 mm when the diameter of the photosensitive drum is 30φ. Then, the contact stop state forming step and the rotation driving step described above are repeated. The number of repetitions is arbitrary, and an additional transfer movement step is interposed between the number of repetitions.

  As a result, the cleaning marks of Y, M, C, and Bk that are shifted by the process pitch from the leading edge to the trailing edge of the recording paper P are cleaned as shown in FIG. Number of times.

  When cleaning is completed as described above, the recording paper P is discharged out of the apparatus through the same conveyance path as that of general recording paper.

  In the above example, all Bk, C, M, and Y photoconductors are cleaned. However, only the Bk photoconductor can be cleaned.

  FIG. 3 shows a state of the image forming apparatus 100 when only the Bk photoconductor is cleaned. In the figure, the unit of the transfer belt 7 and the transfer rollers 6a to 6d are rotated downward with the pulley 73 side as a fulcrum. At this time, the transfer roller 6a and the transfer belt 7 are not separated from the Bk photosensitive drum 3a. Then, one A4 size thick recording paper P is used as a cleaning sheet. The orientation of the recording paper P is such that the short side is along the transport direction. The vicinity of the rear end of the recording paper P is sandwiched between registration roller pairs 14. In this way, the contact stop state forming step and the rotation driving step described above are performed. When these steps are repeated, an additional transport movement step is further performed. After the cleaning is completed in this way, the recording paper P is discharged out of the apparatus through the same conveyance path as that for forming an image of only Bk.

  Next, FIG. 4 shows a flowchart for explaining the above-described photosensitive member cleaning method.

  The start is to enter the cleaning mode by reading and executing a program for executing the method of cleaning the photosensitive member from the key operator unit 52 shown in FIG. 7 by a serviceman or the like.

  In S <b> 1, it is determined whether or not the mode selected by the key operator unit 52 is a color mode in which cleaning is performed for all Bk, C, M, and Y photoconductors. If it is the color mode, the process proceeds to S2, and if it is not the color mode, the process proceeds to S6 described later. In S2, the unit of the transfer belt 7 and the transfer rollers 6a to 6b are brought into contact with all the image forming stations as the positions where the rollers are rotated and raised.

  In S3, it is determined whether or not the cleaning condition is satisfied. The cleaning conditions include completion of conveyance of the recording paper P, completion of application of charging voltages, developing biases, and transfer voltages of the chargers 1a to 1d. The recording paper P is conveyed from the manual feed tray or the paper feed cassette 10 to the image forming station by an input operation in the key operator unit 52, but the light detection unit including the pair of the illumination 21 and the line sensor 22 shown in FIG. Whether or not the conveyance of the recording paper P is completed is determined by whether or not the paper is detected within a predetermined time such as 10 seconds after the start of the paper. Whether or not the high voltage application is completed can be electrically detected. For example, the charging voltage (grid bias) is 700 V, the developing bias is 500 V, the transfer voltage is 500 V, and this value is always output during cleaning.

  If such a cleaning condition is satisfied in S3, the process proceeds to S4, and if not satisfied, the process returns to S1.

  In S4, cleaning is performed under the condition for cleaning all the photoconductors of four colors. At this time, the speed of the photosensitive drums 3a to 3d is controlled to a specified speed such as 117 mm / sec. The number of rotations is a predetermined number, but since the speeds of the photosensitive drums 3a to 3d are determined, the desired number of rotations is controlled in a predetermined time such as 5 seconds. Further, when the additional transport step is performed in order to perform cleaning a plurality of times, a moving time of the recording paper P of 20 msec is provided. Accordingly, when cleaning is performed for 5 seconds, the process of moving the recording paper P in 20 msec and cleaning for 5 seconds is repeated.

  In S5, it is determined whether or not the cleaning has been completed due to the discharge of the recording paper. If completed, the flow is terminated, and if not completed, the process returns to S3. For example, if the number of cleanings is 75, the operation time in the color mode requires 6 minutes and 45 seconds, but this operation time can be set in advance.

  If the color mode is not set in S1, the process proceeds to S6, and it is determined whether or not the mode is the monochrome mode for cleaning only the Bk photoconductor. If it is in the monochrome mode, the process proceeds to S7, and if it is not the monochrome mode, the process returns to S1. In S7, only the Bk image forming station is used as the position where the unit of the transfer belt 7 and the transfer rollers 6b to 6d are rotated and lowered.

  In S8, it is determined whether or not the cleaning condition is satisfied. The cleaning conditions include completion of conveyance of the recording paper P and completion of application of the charging voltage, developing bias, and transfer voltage of the charger 1a corresponding to Bk. For example, the charging voltage (grid bias) and the developing bias are those used during normal image formation, the transfer voltage is 500 V, and these values are always output during cleaning.

  If such a cleaning condition is satisfied in S8, the process proceeds to S9, and if not satisfied, the process returns to S6.

  In S9, cleaning is performed under the condition for cleaning the Bk photoconductor. At this time, the speed of the photosensitive drum 3a is controlled to a specified speed such as 140 mm / sec. The number of rotations is a predetermined number, but since the speed of the photosensitive drum 3a is determined, the desired number of rotations is controlled in a predetermined time such as 3 seconds. Further, in order to perform cleaning a plurality of times, when the additional conveyance step is performed, a moving time of the recording paper P of 30 msec is provided. Accordingly, when cleaning is performed for 3 seconds, the recording paper P is moved within 30 msec, and cleaning is performed for 3 seconds.

  In S10, it is determined whether or not the cleaning has been completed due to the discharge of the recording paper. If it has been completed, the flow ends. If not, the process returns to S8. For example, if the number of cleanings is 50, the operation time in the color mode requires 2 minutes and 45 seconds, but this operation time can be set in advance.

  The above is the flow of the photoconductor cleaning method, but there is no difference in the image quality of the image formed before and after the cleaning in both the color mode and the black and white mode, and there is no problem.

  Next, another example of the method for cleaning the photoconductor will be described.

  5A and 5B, the image forming apparatus 100 is configured to perform cleaning of the photoconductor one by one from the most upstream photoconductor drum 3a to the downstream photoconductor drum in the conveyance path. It is a figure which shows the state of. As the cleaning sheet, one A4 size thick recording paper P is used. The orientation of the recording paper P is such that the short side is along the transport direction.

  First, when cleaning the Bk photoconductor, as shown in FIG. 5A, the vicinity of the rear end of the recording paper P is held between the registration roller pair 14 in the contact stop state forming step. In the rotational drive step, only the photosensitive drum 3a is rotationally driven. When the cleaning of the Bk photoconductor is repeated, the additional transport movement step described above is performed.

  Next, when the C photoconductor downstream of Bk is cleaned, as shown in FIG. 5B, the recording paper P is conveyed to the lower side of the C photoconductor drum 3b, and the C photoconductor is moved. The recording paper P is brought into contact with the position so as to avoid the Bk cleaning mark. At this time, the vicinity of the rear end of the recording paper P is sandwiched between the stopped Bk photosensitive drum 3a on the upstream side and the stopped transfer roller 6a (the transfer belt 7 is also sandwiched). Thus, the contact stop state forming step is performed. Subsequent rotational drive steps are the same as in Bk.

  In this way, the M and Y photoconductors are sequentially cleaned in the same manner as the C photoconductor by sandwiching the vicinity of the rear end of the recording paper P between the one upstream photoconductor drum and the transfer roller.

  By such cleaning, even if a small-sized recording sheet that does not contact all the photosensitive drums 3a to 3d at a time is used, it is possible to clean all of the plurality of photosensitive members. In addition, when cleaning the photosensitive drums of the photosensitive drums positioned at the second and subsequent positions in the conveying direction of the conveying path corresponding to C, M, and Y, the photosensitive drum one upstream of the recording paper; and Since it is sandwiched between the transfer rollers and stopped, when using a small size recording paper, the surface of the plurality of photoconductors can be provided without providing a special mechanism for stopping the recording paper at a plurality of predetermined positions. Can be easily cleaned sequentially.

  Although the above-described photoconductor cleaning method can be realized by a program as described above with reference to FIG. 7, it may be configured by hardware logic. When performed by a program (software), the details can be realized as follows, for example.

  That is, the image forming apparatus 100 includes a central processing unit (CPU) that executes instructions of a control program that implements each function, a read only memory (ROM) that stores the program, and a random access memory (RAM) that expands the program. And a storage device (recording medium) such as a memory for storing the program and various data. An object of the present invention is to supply the control unit 50 with a recording medium in which a program code (execution format program, intermediate code program, source program) of a software control program that realizes the functions described above is recorded so as to be readable by a computer. However, this can also be achieved by reading and executing the program code recorded on the recording medium by the computer (or CPU or MPU).

  Examples of the recording medium include a tape system such as a magnetic tape and a cassette tape, a magnetic disk such as a floppy (registered trademark) disk / hard disk, and an optical disk such as a CD-ROM / MO / MD / DVD / CD-R. Card system such as IC card, IC card (including memory card) / optical card, or semiconductor memory system such as mask ROM / EPROM / EEPROM / flash ROM.

  The control unit 50 may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited. For example, the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network, telephone line network, mobile communication network, satellite communication. A net or the like is available. Also, the transmission medium constituting the communication network is not particularly limited. For example, even in the case of wired such as IEEE 1394, USB, power line carrier, cable TV line, telephone line, ADSL line, etc., infrared rays such as IrDA and remote control, Bluetooth ( (Registered trademark), 802.11 wireless, HDR, mobile phone network, satellite line, terrestrial digital network, and the like can also be used. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

  The present invention can be applied not only to an image forming apparatus having an arbitrary number of photosensitive drums but also to an image forming apparatus of a number electrostatic recording system.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. That is, embodiments obtained by combining technical means appropriately changed within the scope of the claims are also included in the technical scope of the present invention.

  The present invention can be suitably used for a copying machine, a multifunction machine, a facsimile machine, and the like.

FIG. 2 is a cross-sectional view illustrating an embodiment of the present invention and a state of an image forming apparatus performing an example of cleaning of a photoreceptor. FIG. 6 is a plan view of a recording sheet showing a state of a cleaning mark attached to the recording sheet. FIG. 9 is a cross-sectional view illustrating an embodiment of the present invention and a state of an image forming apparatus that performs another example of cleaning of a photoreceptor. 5 is a flowchart illustrating an embodiment of the present invention and a flow of processing in cleaning a photosensitive member. (A) And (b) shows embodiment of this invention and is sectional drawing which shows the state of the image forming apparatus which is performing the further another example of the cleaning of a photoreceptor. 1, showing an embodiment of the present invention, is a cross-sectional view showing a main configuration of an image forming apparatus. FIG. FIG. 7 is a block diagram illustrating a configuration of a control unit and a control block configuration of the image forming apparatus in FIG. 6.

Explanation of symbols

3a to 3d Photosensitive drum 6a to 6d Transfer roller 100 Image forming apparatus

Claims (10)

A contact stop state forming step for forming a contact stop state in which the recording paper transported by the recording paper transport path is brought into contact with the surface of the photoreceptor of the photosensitive drum to stop the recording paper;
A rotational drive step of rotationally driving the photosensitive drum in the contact stop state;
And cleaning the surface of the photoconductor by performing the steps.   2. The photosensitive member cleaning method according to claim 1, wherein, in the rotation driving step, the number of rotations in the rotation driving of the photosensitive drum is 1 to 5 times. After the rotational drive step, an additional transport movement step is performed to transport the recording paper used for cleaning further downstream in the transport direction,
After the additional transport movement step, the contact stop state forming step and the rotation driving step are repeated using the recording paper transported and moved by the additional transport movement step with respect to the same photosensitive drum. The method for cleaning a photoreceptor according to claim 1. When there are a plurality of the photosensitive drums along the transport path,
In the contact stop state forming step, one recording sheet is brought into contact with all the photosensitive drums,
2. The photosensitive member cleaning method according to claim 1, wherein in the rotation driving step, all the photosensitive drums are driven to rotate. After the rotational drive step, an additional transport movement step is performed for transporting the recording paper used for cleaning further downstream in the transport direction by a distance shorter than the distance between the adjacent photosensitive drums,
After the additional transport movement step, the contact stop state forming step and the rotation driving step are repeated using the recording paper transported and moved by the additional transport movement step with respect to all the photosensitive drums. The method for cleaning a photoreceptor according to claim 4. When there are a plurality of the photosensitive drums along the transport path,
Using one sheet of the recording paper, the recording paper is conveyed between the adjacent photosensitive drums one by one from the photosensitive drum on the most upstream side of the conveying path to the photosensitive drum on the downstream side. The method of cleaning a photosensitive member according to claim 1, wherein the contact stop state forming step and the rotation driving step are performed while performing the steps.   In the contact stop state forming step when cleaning the surface of the photoconductor of the photoconductor drum positioned second and subsequent in the transport direction of the transport path, the recording paper is moved up the photosensitive sheet one upstream side. 7. The photosensitive member according to claim 6, wherein the photosensitive drum is stopped by being sandwiched between a photosensitive drum and a transfer roller provided to perform image transfer from the photosensitive drum on the one upstream side. Cleaning method. In an image forming apparatus that forms an image on recording paper using a photosensitive drum,
Forming a contact stop state in which the recording paper transported through the recording paper transport path is brought into contact with and stopped on the surface of the photoreceptor of the photosensitive drum, and rotating the photosensitive drum in the contact stop state. To clean the surface of the photosensitive member.   A program for causing a computer to execute the photosensitive member cleaning method according to claim 1.   A recording medium on which the program according to claim 9 is recorded so as to be readable by a computer.

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